How elementary OS is achieving usefulness?

In a recent blog post, Mr Daniel Fore, a team member of elementary project writes, how elementary OS is achieving usefulness, an essential quality of a successful operating system. He explains how elementary OS allows the users to forget about the operating system and concentrate on their work.

Usefulness is one among the 4 qualities listed by Matthew Paul Thomas, designer at Canonical, as characteristics of a successful operating system. It implies an operating system should be able to do all the things, that people expect their computers to do. Other 3 qualities he listed as characteristics of successful operating system are desirable, get-able and keep-able. He mentioned these qualities in a talk on Ubuntu eco-system.

As MPT explains, the desktop environment provides a foundation for an
operating system’s usefulness, but it is most useful when it fades into
the background and people can hardly tell they’re using it. Pantheon
(the code name for our desktop environment) makes elementary OS useful
with features like an intelligently hiding dock that maximizes screen
real estate, a fast search that enables you to perform actions and find
apps quickly, and a set of full-featured system indicators that help you
keep an eye on the state of your device. But chances are you have never
heard of the name Pantheon, and when you turn on your computer you
don’t set out to use it. What makes an operating system truly useful is
apps.